How is nickel matte produced during smelting?

To produce nickel matte from sulfide ores, the concentrated ore is dried and smelted using flash or bath processes at high temperatures, typically around 1,350 °C (2,460 °F). This smelting process creates an artificial nickel-iron sulfide known as matte, which contains 25 to 45 percent nickel.1

Following the initial smelting, the material undergoes a conversion process in a rotating converter similar to those used in copper production. During this stage, iron in the matte is converted into an oxide, which then combines with a silica flux to form a slag that is drawn off. The removal of sulfur is carefully controlled during this conversion to produce a final matte containing 70 to 75 percent nickel, as this concentration results in a lower melting point compared to pure nickel metal. Throughout these steps, the reaction of oxygen with the iron and sulfur present in the ore helps provide a portion of the necessary heat for the smelting process.12